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At least 1,333 records · Page 74Linked to original sources
PubMed1998

Proteoglycan sulfation in cartilage and cell cultures from patients with sulfate transporter chondrodysplasias: relationship to clinical severity and indications on the role of intracellular sulfate production.

Mutations in the diastrophic dysplasia sulfate transporter (DTDST) gene have been associated with a family of chondrodysplasias that includes diastrophic dysplasia (DTD), atelosteogenesis type 2 (AO2) and the lethal condition achondrogenesis type 1B (ACG1B). There is a correlation between the nature of the mutations and the clinical phenotype, but our understanding of the pathophysiology of the disorder, which involves defective sulfation of cartilage proteoglycans, is far from complete. To evaluate the degree of proteoglycan undersulfation in vivo, we have extracted chondroitin sulfate proteoglycans from cartilage of twelve patients with sulfate transporter chondrodysplasias and analyzed their disaccharide composition by HPLC after digestion with chondroitinase ABC. The amount of non-sulfated disaccharide was elevated in patients' samples (controls, 5.5%+/-2.8 (n=10); patients, 11% to 77%), the highest amount being present in ACG1B patients, indicating that undersulfation of chondroitin sulfate proteoglycans occurs in cartilage in vivo and is correlated with the clinical severity. To investigate further the biochemical mechanisms responsible for the translation of genotype to phenotype, we have studied fibroblast cultures of patients with DTD, AO2 and ACG1B, and controls, by double-labelling with [35S]sulfate and [3H]glucosamine. The incorporation of extracellular sulfate, estimated by the 35S/3H ratio in proteoglycans, was reduced in all patients' cells, with ACG1B cells showing the lowest values. However, disaccharide analysis of chondroitin sulfate proteoglycans showed that these were normally sul fated or only moderately undersulfated; marked undersulfation was observed only after addition of the artificial glycosaminoglycan-chain initiator, beta-D-xyloside, to the culture medium. These results suggest that, while utilization of extracellular sulfate is impaired, fibroblasts can replenish their intracellular sulfate pool by oxidizing sulfur-containing compounds (such as cysteine) and thus partially rescue PG sulfation under basal conditions. This rescue pathway becomes insufficient when GAG synthesis rate is stimulated by beta-D-xyloside. These findings may explain why phenotypic consequences of DTDST mutations are restricted to cartilage, a tissue with high GAG synthesis rate and poor vascular supply, and imply that pharmacological therapy aimed at restoring the intracellular sulfate pool might improve PG sulfation in DTD and related disorders.

Anion Transport Proteins↗
PubMed2002

Insight into Schmid metaphyseal chondrodysplasia from the crystal structure of the collagen X NC1 domain trimer.

Collagen X is expressed specifically in the growth plate of long bones. Its C1q-like C-terminal NC1 domain forms a stable homotrimer and is crucial for collagen X assembly. Mutations in the NC1 domain cause Schmid metaphyseal chondrodysplasia (SMCD). The crystal structure at 2.0 A resolution of the human collagen X NC1 domain reveals an intimate trimeric assembly strengthened by a buried cluster of calcium ions. Three strips of exposed aromatic residues on the surface of NC1 trimer are likely to be involved in the supramolecular assembly of collagen X. Most internal SMCD mutations probably prevent protein folding, whereas mutations of surface residues may affect the collagen X suprastructure in a dominant-negative manner.

Amino Acid Sequence↗
PubMed1989

Serious circulatory disturbance after Le Fort I osteotomy. A case report.

Severe impairment of the blood supply occurred in a patient who underwent a Le Fort I type osteotomy in which the fragment was displaced in a cranio-dorsal direction. Necrosis with sequestration of the torus palatinus present and some permanent parodontal damage ensued. Alternative procedures and management of developing circulatory impairment during surgery are discussed.

Adult↗
PubMed1989

A unilateral mesenchymal disorder of the head.

A hitherto undescribed group of lesions consisting of cystic bony lesions, exostosis, fibromatous lesion, unilateral tonsillar hypertrophy, epidermoid cyst (cholesteatoma) and hyperplasia of the mandible confined to the left side of the face is reported. The case may represent a variant of the Proteus syndrome.

Adult↗
PubMed1999

Discectomy of the temporomandibular joint: an experimental study in monkeys.

Postoperative changes have been observed in the temporomandibular joint (TMJ) after discectomies. Animal models have often shown that interventions in the TMJ may heal uneventfully. Discectomies were performed on 14 Macaca fascicularis and macroscopic and microscopic examination performed after sacrifice of the animals. Two of the animals did not show any apparent macroscopic or microscopic changes. The remaining 12 joints showed minor to major changes. The most serious changes were seen in three joints with fibrous ankylosis and five joints showed marked destruction of the articular cartilage.

Animals↗
PubMed2003

An unusual cause of hiccup: costal exostosis. Treatment by video-assisted thoracic surgery.

The described case is of a 15-year-old boy who presented with a persistent hiccup and repeated episodes of left-sided chest pain. At computed tomography scan an exostosis originating from the costo-chondral junction of the left 4th rib was seen. The tip of the exostosis reached the external surface of the pericardium. Removal of a 2 cm rib segment including the implantation basis of the exostosis was achieved by video-assisted thoracic surgery. Symptoms disappeared after surgery. This report shows an exceptional symptom of costal exostosis.

Adolescent↗
PubMedDate not supplied

Arthroscopic partial resection of the scapula for snapping scapula: a new technique.

We describe a new method of arthroscopic bony surgery to the superomedial corner of the scapula in patients with painful snapping caused by bony impingement. Seven patients who had failed conservative treatment were monitored prospectively. In 5 patients we used 3-dimensional computed tomography as a diagnostic aid. The condition was successfully managed in 6 cases. One procedure was abandoned because of intraoperative swelling; there was 1 minor wound infection. In all cases the operation relieved symptoms. Two of the 5 patients scanned had narrowing of the superomedial interval. The advantages of this technique are in cosmesis and early rehabilitation, and the early results are good. Provided due care is taken in portal placement, complications should be minimal. Three-dimensional reconstruction computed tomography scanning may be useful in some patients to show narrowing between the superomedial corner and the chest wall, but we cannot at present recommend its routine use.

Adult↗
PubMedDate not supplied

Extracorporeal shock wave therapy for the treatment of chronic plantar fasciitis: indications, protocol, intermediate results, and a comparison of results to fasciotomy.

A review of the history, mechanism of action, and application of extracorporeal shock wave therapy for chronic plantar fasciitis is presented. The results of 40 feet treated with this modality are reviewed after a mean follow-up time of 8.4 months. All procedures were performed under intravenous sedation and local infiltrative anesthesia. An electrohydraulic shock wave with a mean of 20.6 kV combined with a mean of 2,506 pulses was used. The results of a similar demographic class of patients having undergone a percutaneous plantar fasciotomy at our institution were compared to the results of this cohort of shock wave patients. Eighty-two percent of the patients treated with extracorporeal shock wave therapy were successfully treated as compared to 83% with a percutaneous plantar fasciotomy. The mean score on the 11-point visual analog scale for satisfied patients was 7.9 preoperatively and 2.95 within 7 days postoperatively. After 3 months, the mean visual analog score was 4.2 or 50% of the preoperative value after a mean of 8.4 months following treatment. Eighty-three percent of the patients treated stated that shock wave therapy improved their symptoms. There were no complications encountered in any patient in this study. Extracorporeal shock wave therapy is an effective treatment, which significantly reduces the symptoms associated with chronic plantar fasciitis and compares favorably to the results achieved with surgical intervention in the form of a percutaneous plantar fasciotomy.

Adult↗
PubMedDate not supplied

Endoscopic heel anatomy: analysis of 200 fresh frozen specimens.

The authors radiographed and dissected 200 fresh frozen cadaveric specimens selected randomly from the general United States population. A 21% incidence of inferior calcaneal exostosis formation was identified. Of those specimens identified as having an inferior calcaneal exostosis, there was a 52.4% incidence of heel spurs that were in the plantar fascia and a 47.6% incidence of heel spurs that were identified superior to the plantar fascia. After dissection of the specimens, the mean width and thickness of the medial, central and lateral bands of the plantar fascia, and the width of the medial and lateral subcutaneous fat were calculated. The presence of an inferior calcaneal bursa was identified in one specimen, and the presence of a heel neuroma was identified in 0 specimens of the 200 examined. The results of this study will assist the practitioner in performing the endoscopic plantar fasciotomy by providing the surgeon with quantitative averages of fascial dimensions. By knowing these fascial measurements, the practitioner will be aided intraoperatively in determining what level of fasciotomy to perform. This could help obviate some of the postoperative biomechanical sequelae that can occur with total releases, and immediate postoperative excessive ambulation by the patient. This study may help to gain insight into the true etiology of heel spur syndrome/plantar fasciitis.

Arthroscopes↗
PubMedDate not supplied

A new method for reattachment of the tendo Achillis following retrocalcaneal exostectomy.

Currently there are a number of surgical techniques being utilized to address the entity of symptomatic, recalcitrant retrocalcaneal exostosis. This article presents a mechanical study of a modified surgical approach which has been developed at the Northern Virginia Podiatric Residency Program for the purposes of complete resection of all offending exostosis and calcifications, and maintenance of the anatomic configuration of the Achilles tendon with resultant asymptomatic function and cosmetic healing. The centerpiece of the surgical modification is the way in which the portion of reflected Achilles tendon is reattached to the calcaneus, utilizing soft-tissue anchors in combination with a modified Krackow suture technique. In order to delineate the relative strength of this suture technique, a cadaveric study was performed using six specimens. Each specimen underwent tendon repair with both a modified Krackow technique and a modified vertical mattress coaptation technique for a total of 12 studies. The force required to displace the tendon for distances of 0.5 cm and 1.0 cm was then recorded, and the data were statistically analyzed, with the modified Krackow technique proving to have a significantly better ability to resist distractive forces at both 0.5 cm (p = .01) and at 1.0 cm (p = .02) compared to the vertical mattress coaptation technique.

Achilles Tendon↗
PubMed2001

The transcription factors L-Sox5 and Sox6 are essential for cartilage formation.

L-Sox5 and Sox6 are highly identical Sry-related transcription factors coexpressed in cartilage. Whereas Sox5 and Sox6 single null mice are born with mild skeletal abnormalities, Sox5; Sox6 double null fetuses die with a severe, generalized chondrodysplasia. In these double mutants, chondroblasts poorly differentiate. They express the genes for all essential cartilage extracellular matrix components at low or undetectable levels and initiate proliferation after a long delay. All cartilages are thus extracellular matrix deficient and remain rudimentary. While chondroblasts in the center of cartilages ultimately activate prehypertrophic chondrocyte markers, epiphyseal chondroblasts ectopically activate hypertrophic chondrocyte markers. Thick intramembranous bone collars develop, but the formation of cartilage growth plates and endochondral bones is disrupted. L-Sox5 and Sox6 are thus redundant, potent enhancers of chondroblast functions, thereby essential for endochondral skeleton formation.

Animals↗